NO. 1659. AMERICAN SPECIES OE SYNALPHEV8—C0VTIERE. g5 



rying eggs the proportioii-s 1, .5, 1.2. The pahn bears in front a conical 

 tubercle, not spinose, pointing obliquely upward. The movable fin- 

 ger slightly exceeds the fixed finger. 



The small chela measures : Fingers 1 ; total length 2.G ; height 0.95. 

 The fingers terminate in a single point. The carpus measures 0.5 of 

 the whole chela. The meropodite is very thick, only 2.35 times as 

 long as Avide. 



The second pair is very remarkable in that the carpus has only four 

 articles. I have encountered the same number in young specimens of 

 S. longicarpus, and especially of S. hrooksi, but very exceptionally. 

 Here it is a constant character. It is not certain, to tell the truth, that 

 the specimens examined are normal, at least the females. In about 

 thirty of the specimens I have been able to find only five carrying eggs. 

 Four of the.se females each possess but one egg, the fifth has only 

 three. Their abdominal pleura are not only very slightly developed, 

 but they are all terminated by a very sharp point, and the second 

 pleuron is hardly wider than the first and the third. As the total 

 length of the largest specimen is 7.5 mm., it is possible that I have had 

 in my hands only dwarfed or emasculated individuals, not showing 

 the true sexual characters of the species. Perhaps in specimens of 

 larger size, if such exist, the second pair Avould have five segments in 

 the carpus, as in the great majority of the Alpheidai, the genus Arete 

 (with four segments) being the only exception. 



The proportions of the third pair are : Meropodite 2.2 ; carpus 1 ; 

 propodite 1.4. The meropodite, very ma.ssive, is only 2,8 times longer 

 than wide. The two hooks of the dactyl are parallel and equal in 

 length, the ventral, however, the stronger. 



The spines of the dorsal face of the telson are very long and 

 strong. Between the spines of the posterior margin are four plumose 

 hairs. The outer uropod bears three teeth and a longer movable 

 spine very close to the first tooth. 



Named for Miss Mary J. Rathbun, of the U. S. National Museum. 



This species recalls especially S. pescadorensis Coutiere, of the 

 Malayan Archipelago ; besides the exceptional character of the second 

 pair of feet, it differs from the latter species chiefly in the plume of 

 hairs which surmounts the finger of the small chela, as in all the 

 .species of the L.evimanus group. 

 Localities : 



Porto Rico, Mayaguez Harbor, 22 to 83 fathoms. Fish Hawk 



Station No,. GOG-i, on dead sponges, 30 specimens, of which 



about 5 are females, 



Vieques, 12^ fathoms. Fish Hawk Station No, G095, 1 specimen, 



St, Thomas, 20 to 30 fathoms. Fish Hawk Station No. 6079, 7 



specimens, types. 



Type.— Cat. No, 38410, U.S,N,M. 



